The company is worried about exposing children to "external influences."

Microsoft announced during its pre-E3 press event that Minecraft will be updated this fall with 4K graphics and complete cross-platform play, meaning that players on PC, consoles, and mobile devices will all be able to play together—with the one notable exception of Sony, which declined to join the party. The reason for that seemingly odd refusal, PlayStation global sales and marketing head Jim Ryan told Eurogamer, is that Sony believes it's "got to be mindful of our responsibility to our install base."

"Minecraft—The demographic playing that, you know as well as I do, it's all ages but it's also very young. We have a contract with the people who go online with us, that we look after them and they are within the PlayStation curated universe," Ryan said. "Exposing what in many cases are children to external influences we have no ability to manage or look after, it's something we have to think about very carefully."

He acknowledged that Nintendo, which has a far more obvious appeal to younger gamers, was happy to get on board, saying, "Everybody has to take their own decisions." And he also left the door open, ever so slightly, for the situation to change. "I don't think anything is ever a done deal," he said. "Anybody who is dogmatic in that manner is typically a fool."

Microsoft made its position on the matter clear shortly after the cross-platform update was announced.

We would love to have PlayStation players along with the unified Minecraft, hope that we can. https://t.co/hRGPG8Aj8aJune 11, 2017